1. Field of the Invention
The present invention relates to tools for removing the spinal cord from carcasses.
2. Description of Related Art
Spinal cord removal tools are used in the processing of carcasses to remove the spinal cord from the spinal cord channel surrounding it. Complete removal of the spinal cord is difficult due to the many irregularities and protrusions in the bony channel that surrounds it. Accordingly, tools of this type must perform both a cutting and grinding action and may also be referred to as xe2x80x9cspinal cord grinders.xe2x80x9d A related problem is the elongated spinal cord membrane, which tends to wrap around the shaft of motorized removal tools and interfere with operation of the tool and proper removal of the spinal cord.
One tool that addresses these problems in removing the spinal cord is seen in European Patent EP 0 890 313 B1, which uses a motor driven blade disk spinning inside a housing. The blade disk includes multiple spinal cord removal blades oriented perpendicular to the plane of the disk. The removal blades are spaced around the perimeter of the blade disk and project out from the housing on the working side as the disk spins. Each removal blade includes a front cutting edge, a left cutting edge and a right cutting edge.
The front cutting edges are rounded and project outward from the perimeter of the blade disk that supports them. The shape of the removal blades allows them to penetrate into the spinal cord channel to scrape and cut out the spinal cord as the blade disk spins. The operator guides the exposed perimeter of the spinning blade disk, with the protruding removal blades, into the spinal cord channel.
The side cutting edges on the removal blades cooperate with fixed side blades mounted on left and right sides of the housing to cut up the spinal cord membrane as it is brought into the tool. The fixed side blades are mounted at an angle to the spinning side edges of the removal blades and provide a scissors-like cut to shear the spinal cord membrane and cut it into smaller pieces. A vacuum opening is located inside the tool near the side blades to remove the waste material
One difficulty with the tool shown in EP 0 890 313 B1 is the fixed location of the side blades relative to the side edges of the removal blades. Because the side blades are located a fixed distance apart, it is difficult to manufacture the tool. The removal blades must be ground so that their left and right side edges are exactly the same distance apart as the distance between the non-adjustably mounted side blades.
As the blades wear, it becomes desirable to sharpen them. However, sharpening must be completed without affecting the distance between the left and right side edges of the removal blades or the location of the cutting edges on the fixed side blades. When the side blades fail to shear the spinal cord membrane, it wraps onto the shaft of the tool. The tool must then be disassembled and cleaned and new blades must be installed.
Bearing in mind the problems and deficiencies of the prior art, it is therefore an object of the present invention to provide a spinal cord removal tool with side blades that are manually or automatically adjustable to move towards and away from the side edges of the removal blades to compensate for wear, changes due to sharpening or manufacturing tolerances.
Still other objects and advantages of the invention will in part be obvious and will in part be apparent from the specification.
The above and other objects, which will be apparent to those skilled in art, are achieved in the present invention, which is directed to a spinal cord removal tool for removing a spinal cord and spinal cord membrane from a carcass. The tool includes a motor, a housing, and a blade disk mounted in the housing. Multiple spinal cord removal blades are mounted around the perimeter of the blade disk, each removal blade having a front cutting edge, a left cutting edge and a right cutting edge. The motor spins the blade disk within the housing and a portion of the blade disk, is exposed on a working side of the tool.
The operator aligns the plane of the spinning blade disk with the spinal cord channel and brings the working side into contact with the spinal cord channel to begin the removal process. The shape of the removal blades allows them to enter the channel and remove the spinal cord and spinal cord membrane.
The blade disk spins between a left side blade and a right side blade. The side blades are mounted on the housing for motion towards and away from the left and right cutting edges of the spinal cord removal blades. A left side adjustment mechanism adjusts the left side blade relative to the left cutting edges of the spinal cord removal blades. A right side adjustment mechanism adjusts the right side blade relative to the right cutting edges of the spinal cord removal blades.
In a first embodiment the right and left side adjustment mechanisms are self-adjusting and provide a floating mount for the side blades. In this embodiment, the side blades are straight and always contact at least two edges of the removal blades. The side blades are urged towards the side cutting edges of the removal blades by one or more springs. The floating spring mounting of the side blades allows them to automatically compensate for any changes in the location of the cutting edges due to wear or sharpening.
In a second embodiment the right and left side blades are curved and are always in contact with at least three edges of the removal blades. Each side blade is preferably urged towards the facing side cutting edges of the removal blades by three springs, which provide three floating mounts for each blade. The additional curved length of the side blades and the additional contact with the side cutting edges of the removal blades provides more blade support and allows the tool to operate at higher speeds.
In a third embodiment of the invention the right and left side adjustment mechanisms comprises right and left side manual adjustment mechanisms, which include corresponding right and left side adjustment screws for moving the right and left side blades towards and away from the cutting edges of the spinal cord removal blades. Preferably, the side blades are straight and include a pair of adjustment screws, located at each end, with corresponding lock screws for locking the adjustment after it has been set manually. The manual adjustment allows the clearance between the side blades and the removal blades to be very accurately controlled and adjusted for improved cutting performance, reduced blade chatter and low noise, particularly when the tool is operated at very high speeds.